Oracle® Coherence Java API Reference
v3.5.3

E15583-01

com.tangosol.util
Interface TransactionMap.Validator

All Known Implementing Classes:
SimpleValidator
Enclosing interface:
TransactionMap

public static interface TransactionMap.Validator

A callback interface used by TransactionMap implementations.

By providing an implementation of this interface, it is possible to provide alternative strategies for verifying the correctness of concurrent execution of transactions.


Method Summary
 void enlist(TransactionMap mapTx, java.lang.Object oKey)
          Enlist the resource with the specified transaction.
 TransactionMap.Validator getNextValidator()
          Retrive the next Validator.
 void setNextValidator(TransactionMap.Validator v)
          Set the next Validator.
 void validate(TransactionMap mapTx, java.util.Set setInsert, java.util.Set setUpdate, java.util.Set setDelete, java.util.Set setRead, java.util.Set setPhantom)
          Validate that the content of the TransactionMap is "fit" to be committed into the base map.
 

Method Detail

enlist

void enlist(TransactionMap mapTx,
            java.lang.Object oKey)
Enlist the resource with the specified transaction.

This method is invoked for all resources that are "used" by the transaction immediately before the resource value is copied into the local map.

It is this method's responsibility to call a next Validator in the validation chain (i.e. getNextValidator().enlist(map, okey);)

Parameters:
mapTx - the TransactionMap to enlist the resource with
oKey - the resource key to be enlisted with the transaction

validate

void validate(TransactionMap mapTx,
              java.util.Set setInsert,
              java.util.Set setUpdate,
              java.util.Set setDelete,
              java.util.Set setRead,
              java.util.Set setPhantom)
              throws java.util.ConcurrentModificationException
Validate that the content of the TransactionMap is "fit" to be committed into the base map.

This method is invoked during "prepare" phase after all the resources involved in this transaction are successfully locked at the base map. The Validator is expected to retrieve the "old" and "new" values (using map.get(oKey), map.getBaseMap().get(oKey)) and use the information gathered during "enlist" calls to make the determination whether or not commit should be allowed to proceed.

To force a roll back it should throw an exception indicating the reason this transaction cannot be committed. When that happens, the sets are expected to hold just the keys of the "offending" resources.

It is this method's responsibility to call a next Validator in the validation chain (i.e. getNextValidator().validate(map, setI, setU, setD, setR, setF);)

Parameters:
mapTx - the TransactionMap that is being prepared
setInsert - the set of inserted resources
setUpdate - the set of updated resources
setDelete - the set of deleted resources
setRead - the set of read resources. It is always empty for TRANSACTION_GET_COMMITTED isolation level.
setPhantom - the set of phantom resources, that is resources that were added to the base map, but were not known to the transaction. This set can be not empty only for TRANSACTION_GET_SERIALIZED isolation level.
Throws:
java.util.ConcurrentModificationException - if the validator detects an unresolveable conflict between the resources

getNextValidator

TransactionMap.Validator getNextValidator()
Retrive the next Validator.

Returns:
the next Validator

setNextValidator

void setNextValidator(TransactionMap.Validator v)
Set the next Validator. Note: This method cannot be called while in the middle of a validation (commit) phase.

Parameters:
v - the Validator to be added
Throws:
java.lang.IllegalStateException - if the next validator cannot be changed

Oracle® Coherence Java API Reference
v3.5.3

E15583-01

Copyright © 2000, 2010, Oracle. All rights reserved.